O2 millivolts to lambda ?

[Swede2]

Hi!

I wonder about what the o2 millivolts actually say ? I know that high (800-) is rich and low (720-750) is lean... But can I use this numbers to anything else? For example convert it to european lambda numbers ? Or is that the only function on the o2 sensor ? To give me the voltage numbers I mean.

If not, are there any other way to get lambda values except a broadband sensor ?

Daniel

 

[Swede2]

Hmm, was it a silly question or is it not intresting or maybe its a to hard question ? lol

Daniel

 

[ijames]

The stock sensor is only accurate at an air-fuel ratio of 14.7, or lambda of 1. We use them for tuning at WOT because we have them and because they are better than nothing and because they are surprisingly reproducible, but they are not accurate enough to use to actually calculate a lambda or air-fuel ratio. Their response is both temperature and exhaust back-pressure dependent, and will get fooled by misfires. That's why tuners suggest working up a tune on a particular car by using the O2's along with plug reading, knock, egt, and whatever else you can, then using the final O2 values to track the tune to catch when something else drifts. I've seen tables of O2 millivolts vs. air-fuel ratio, and they may even have been accurate for some sensor under a particular set of conditions, but not for any other sensor .

 

[Swede2]

Thanks for the answer. It seems to be like I guessed, the sensor is not so accurate. But it will be enough for me at this point, I have almost a stock engine.

Daniel